You can run the tests from the command line, by using the -t or --run-test options.

Run all tests:

freecad--run-test0

Run only some the specified unit test, for example:

freecad-tTestDraft

Test menu

Each top level directory in FreeCAD should have a file with the tests that can be run for that particular workbench or module. The file usually starts with the word Test.

To run a test from within FreeCAD, switch to the Test Workbench, then Test commands → TestToolsGui → Self test → Select test name, then enter the name of the Python file with the tests; for example, for the Draft Workbench, this would be TestDraft, then press Start.